Concept Lab Prep Instructions
Major Items to Prepare # Agar Cubes: 2+ days prior # Pasteur's Experiment x 3: 2 weeks prior # Copy Safety Agreements # Extra copies of Concept lab for students who have not yet bought the manual Agar Cubes About These will be used in Exercise 1, as an example of surface to volume ratio. In this exercise, the students will soak the 2 sized cubes in an acid (25% vinegar) which will make the purple indicator turn clear from the outside-in. The higher the surface to volume ration, the faster the cube will turn clear. This is an exercise to demonstrate many things in biology having to do with surface area, particularly the small size of a cell. Instructions *Prepare 6 large (~2cm) cubes and 6 small (~1cm) cubes for each class section + some extras for good measure Materials: * Bromeresol Purple .4% (0.4g powder + 99.6mL H2O) * 10g agar * 450 mL DI H2O * 50mL .01M NaOH * 5 mL Bromocresol Purple Methods # In 500mL media bottle, add 10g of agar powder # Add 395mL H2O # To make cubes, melt the agar, # Add 50mL .01M NaOH, and 5 mL Bromocresol Purple # Stir for hours or overnight to fully dissolve the indicator # Autoclave and store # To make cubes, put the bottle in a warm bath to melt the agar # Once melted, mix gently and pour into square container # Let sit or refrigerate until solid # Remove from container # Cut 2 cm and 1 cm cubes (I haven't found a great way to do this yet so do the best you can). Location of Materials * Bromocresol Purple: Chemical Cupboard C9 * Agar: Media cupboard C10 * Cube Tray: Drawer next to Bench sink? * NaOH: Base cupboard in Room 317 Instructions Improvement Notes Add an approximation of how much this recipe will make Pasteur's Experiment About This is an amazing experiment that covers the scientific method. This is for Exercise 2. Instructions Prepare '' 3 SETS ''of the experiment. There will be 3 stations in each lab for this one single exercise. Materials and Methods Prepare 18 x 500mL flasks with 200mL nutrient broth in each. You only need 15 but I always make a couple extra just in case of contamination. Follow the instructions on the bottle but... Nutrient Broth (These are instructions for 1 L of broth. I usually fix up 3600mL for about 18 flasks) # Suspend 8 g of nutrient broth powder in 1L of DI water. # Mix thoroughly on a hot plate # Boil for 1 minute to dissolve the powder # Aloquot 200mL into individual 500 mL flasks # Autoclave all flasks with stoppers on liquid for 15 minutes (121 degrees) # All stoppers and tubes that will be used must be autoclaved too # Immediately put appropriate stoppers and tubes on the flasks after autoclaving Flasks * A: Inoculate 3 open flasks with yucky swabs from yucky places and incubate * B: Pour 3 into new, un‐autoclaved flasks and close * C: Keep 3 Sealed completely with #7 stoppers, do not open after leaving the autoclave * D: Affix 3 with straight glass tubes before autoclaving * E: Affix 3 with hook tubes before autoclaving Location of Materials * Nutrient agar: Media Cupboard C10 Original Notes* Category:Bio 10 Concepts Lab Set-Ups